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Cellular Oncology
Volume 27, Issue 3, Pages 183-190

Quantitative Analysis of Chemotherapeutic Effects in Tumors Using In Vivo Staining and Correlative Histology

Heung Kook Choi,1,2 Doreen Yessayan,1 Hyun Ju Choi,2 Eyk Schellenberger,1 Alex Bogdanov,1 Lee Josephson,1 Ralph Weissleder,1 and Vasilis Ntziachristos1

1Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
2School of Computer Engineering, Inje University, Gim-Hae, Republic of Korea

Copyright © 2005 Hindawi Publishing Corporation and the authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Aims: To microscopically analyze the chemotherapeutic response of tumors using in vivo staining based on an annexinV-Cy5.5 probe and independently asses their apoptotic count using quantitative histological analysis. Methods: Lewis Lung Carcinomas cells, that are sensitive (CS-LLC) and resistant (CR-LLC) to chemotherapy were implanted in nude mice and grown to tumours. Mice were treated with cyclophosphamide and injected with a Cy5.5-annexinV fluorescent probe. In vivo imaging was performed using Fluorescence Molecular Tomography. Subsequently tumours were excised and prepared for histology. The histological tumour sections were stained for apoptosis using a terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay. A minimum of ten tissue sections were analyzed per tumour for apoptosis quantification by TUNEL staining and corresponding Cy5.5 distribution. Results: We detected higher levels of apoptosis and corresponding higher levels of Cy5.5 fluorescence in the CS-LLC vs. the CR-LLC tumours. The cell count rate on CS-LLC sections over CR-LLC was found to be ∼2 :1 where the corresponding area observed on Cy5.5 distribution measurements revealed a ∼1.7 :1 ratio of CS-LLC over CR-LLC. These observations are consistent with the higher apoptotic index expected from the CS-LLC cell line. Conclusions: Quantitative analysis of histological slices revealed higher fluorescence and higher apoptotic count in the CS-LLC tumour images compared to the CR-LLC tumour images. These observations demonstrate that the annexinV-Cy5.5 probe sensed the chemotherapeutic effect of cyclophospamide and further confirmed in vivo FMT measurements.